TY - JOUR
T1 - Change of deformation mode caused by aging of Ti-14 mass%Mo alloy single crystals and embrittlement mechanism due to the ω-phase
AU - Takemoto, Yosito
AU - Hida, Moritaka
AU - Sukedai, Eiiti
AU - Sakakibara, Akira
N1 - Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 1989
Y1 - 1989
N2 - A change of deformation modes in lattice instable Ti-14 mass%Mo alloy single crystals upon aging treatments at 623 K was investigated in the tensile test up to rupture. The tensile direction of these specimens was [116]B. The main deformation modes of as-quenched specimen (AQ) were {332} 〈113〉 and {112} 〈111〉 mechanical twins. Their Schmid factors (SF) were 0.321 and 0.156 in {332} 〈113〉 twins and 0.447 in {112} 〈111〉 twins. A specimen aged for a short time of nearly 250 s (AG (S)) showed a kind of transitional state of deformation mode which involved {332} 〈113〉 twins, {112} 〈111〉 twins and {112} 〈111〉 slips. In this state AG(S) had been already poor in ductility. A specimen long aged for 1 × 105 s (AG(L)) showed a remarkable brittle fracture caused by the aged ω phase, but it was not the {001} cleavage fracture. The fracture surface had a chevron pattern induced by the operation of some {112} slip systems in the initial stage. Large grown aged ω variants caused the B matrix to remarkably increase the stress level for deformation and induced locally an Ω→B inverse transformation. Local softening which occurred with the inverse transformation led to an extreme stress concentration and then to crack. In this way AG(L) apparently showed notable embrittlement.
AB - A change of deformation modes in lattice instable Ti-14 mass%Mo alloy single crystals upon aging treatments at 623 K was investigated in the tensile test up to rupture. The tensile direction of these specimens was [116]B. The main deformation modes of as-quenched specimen (AQ) were {332} 〈113〉 and {112} 〈111〉 mechanical twins. Their Schmid factors (SF) were 0.321 and 0.156 in {332} 〈113〉 twins and 0.447 in {112} 〈111〉 twins. A specimen aged for a short time of nearly 250 s (AG (S)) showed a kind of transitional state of deformation mode which involved {332} 〈113〉 twins, {112} 〈111〉 twins and {112} 〈111〉 slips. In this state AG(S) had been already poor in ductility. A specimen long aged for 1 × 105 s (AG(L)) showed a remarkable brittle fracture caused by the aged ω phase, but it was not the {001} cleavage fracture. The fracture surface had a chevron pattern induced by the operation of some {112} slip systems in the initial stage. Large grown aged ω variants caused the B matrix to remarkably increase the stress level for deformation and induced locally an Ω→B inverse transformation. Local softening which occurred with the inverse transformation led to an extreme stress concentration and then to crack. In this way AG(L) apparently showed notable embrittlement.
UR - http://www.scopus.com/inward/record.url?scp=0024752860&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0024752860&partnerID=8YFLogxK
U2 - 10.2320/jinstmet1952.53.10_1004
DO - 10.2320/jinstmet1952.53.10_1004
M3 - Article
AN - SCOPUS:0024752860
VL - 53
SP - 1004
EP - 1012
JO - Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
JF - Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
SN - 0021-4876
IS - 10
ER -